Two ships -- one piloted by Daleks, the other by a team of humans --
crashlands on Exxilon. Both groups have come to Exxilon in search of the
mineral parrinium, the only cure for a space plague which is wreaking
havoc throughout the cosmos. The Doctor and Sarah discover that both
parties have been mysteriously rendered powerless, meaning that the
Daleks' weapons are inoperable -- and they have begun acting unusually
cooperative as a result. As his oldest foes begin to show their true
colours, however, the Doctor must brave the dangers of the lost city of
the Exxilons in order to deliver the parrinium into the rightful
hands.

Production

Doctor Who producer Barry Letts was keen to use the Daleks once
again in the programme's eleventh season. Letts was aware that the
venerable monsters continued to attract considerable publicity, and felt
that having them appear mid-year -- as with Season Ten's Planet Of The Daleks -- would provide Doctor
Who with a ratings boost. In accordance with the agreement reached
between the Doctor Who production office and Dalek creator Terry
Nation, Nation was given first refusal on writing the new serial, and for
the second year running, he agreed to provide the scripts himself.

Nation began developing a storyline from an idea suggested by script
editor Terrance Dicks. Commissioned on March 23rd, 1973, this involved an
intergalactic quest to find the cure to a space plague, and a
once-sophisticated society which had reverted to barbarism. Inspired by
the “elixir” which was the core of the adventure, Nation gave
the story the working titles “The Exilons” and then “The
Exxilons” after the new aliens he had created. Robert Holmes, who
was trailing Terrance Dicks in anticipation of becoming Doctor
Who's new script editor, suggested that the connection between the
aliens' name and the elixir (which the Exxilon city was also to have been
reliant upon) was too obvious, and so this was amended to a mineral,
parrinium.

Robert Holmes may have suggested the title Death To The Daleks, as he disliked the famous
monsters

It may also have been Holmes who suggested the title Death To The
Daleks for Serial XXX, as he disliked the famous monsters. Several
modifications were made to avoid similarities with Planet Of The Daleks: the jungle-choked Exxilon
became rocky and barren, while the humans were more securely established
than the hunted Thals of the previous story. Another significant change
was to the climax: originally, the Daleks escaped with the cure, but the
humans worked with the Exxilons to set them back on the path to
advancement and were given more of the cure in return. The subterranean
Exxilon Gotal was originally called Jebal. Scripts for Death To The
Daleks were commissioned on July 2nd.

The story's director was Michael Briant, who had last worked on The Green Death the year before. Location
filming spanned five days in November -- the 13th to the 16th, and the
19th -- at the ARC Sand Pits at Gallows Hill, Dorset which served as the
surface of Exxilon. No new Dalek casings were constructed for the serial;
indeed, because of the unsatisfactory quality of the new Daleks made for
Planet Of The Daleks, most of those used on
Death To The Daleks were casings surviving from the Sixties.

Throughout the Pertwee era, the usual studio schedule had involved two
consecutive recording days every fortnight, with each day typically
concentrating on completing all scenes from a single episode. Briant
elected to experiment with this scheme: in order to further decrease wear
and tear on the sets (the motivation behind switching from the earlier
method of taping one episode every week), he decided to record material
set-by-set rather than in story order. Moreover, Briant confined all
recording to the second day of each two-day block, with the first day used
purely for camera rehearsals.

Other departures, boredom, back pain, and salary issues
all convinced Jon Pertwee that it was time to leave Doctor Who

Taping under this revised approach began on Monday, December 3rd and
Tuesday the 4th in BBC Television Centre Studio 4. Unfortunately, Briant's
efforts were undermined when several props and sets went missing.
Furthermore, the cast found the demanding recording schedule on the
Tuesday to be very exhausting -- a situation not ameliorated by Jon
Pertwee's increasingly disinterested attitude toward Doctor Who.
Death To The Daleks was completed exactly two weeks later, on the
17th and 18th, again in TC4.

Prior the start of studio recording, Barry Letts had made it known to the
cast and crew that he had decided to leave Doctor Who following
Season Eleven, his fifth on the programme. This meant that in the span of
a year, three key ingredients of the series' Seventies revitalisation --
Letts, Dicks, and Katy Manning, who had played companion Jo Grant -- had
elected to move on, while villainous mainstay Roger Delgado (the Master)
had perished in an auto accident. Furthermore, the recurring UNIT
characters -- Brigadier Lethbridge Stewart, Captain Yates and Sergeant
Benton -- had been featured more and more infrequently of late. These
factors, combined with his mounting boredom and chronic back pain, finally
convinced Pertwee that it was time to leave Doctor Who, especially
after his request for a significant raise was turned down in late 1973.
After an unprecedented five years, it was once again time to search for a
new Doctor...

Sources

Doctor Who: The Handbook: The Third Doctor by David J Howe and
Stephen James Walker (1996), Virgin Publishing, ISBN 0 426 20486 7.